Method for vaporizing sulfur



Jan. 15, 1952 c. A. PORTER ETAL METHOD FOR VAPORIZING SULFUR Filed May 25, 1946 Malian Uhazye i110 Sulfur/1' /Pump /5 Q A Sulfur q I flare U 8 ng' amf aarBonaceou-s Scum Drawgfi Recirculaiing INVENTORS W ll gs m ATTO Y 19%212ZDrum T Sul lfizrVapor SulfurDra fiise Se uuiLeveZ llhai'les 4pm;- Gear 5 6iz'cu Zating"Pungp 9x1.

ing'Po CZeanJIbT/Zen S u .1413 B0 E a i M w w w mu MM, 2 Hum saws n m 0 MM WU Z iqui M :iIltO drum 9. The "iiiiid'e filblttiil V it is charged to line is heatiit'o atfliperatiife sufficient to liquifyftlie sulfur, but not in excess of about '1'50'"C. Careshould be exercised not i atented Jan. 15, 1 952 One of the objects of our inventiongis to pfmvide a continuous methodfor vaporizing crude re ,e A, v, Another object of ;our inventio nf1 s to provide apparatus 'for the continuous vaporization of crude sulfur.

Other objects otth e invention win appear 3 from the following description and accompanyawi i-W i h r t, Figure l is a diagrammatic,elevatldnal'viw "of -the apparatus in accordance with air "invention; and g Figurez is 'afvie'w pal-myth vertical 'cfofss sfction "of "a'modi'fid forfifi of hat'r'foi'ilse the apparatus sliownin F gure :1. p 7 Referring fpa'fticfilarlyto'the 1112. the nume al 1 indicates j'a lifie through "wm h molt'n suuur is eriar'gea 'bwmea 's of pump line 5, valves ligand 1 and distributor "hafd 8 B'fb'f to heat the sulfurtda-temperature at which it becomes viscous.

' withdrawn frdin'thesiirfaceof tlie molten s fur may be treated to recover the sulfur contained therein or the scum may be otherwise disposed 'of. Any sludge which may settle out of the sulfur is withdrawn from the bottom of the drum 9 through withdrawal lines 15, controlled by valves [1 and I9. The sludge withdrawal may be intermittent or continuous depending upon the amount of sludge which settles to the bottom of the drum. A suitable sight glass (not shown) mayfbep'fovfded onfh'eout'sideo'f mediumm ofrder to determine the ieveror the sludge inthe Manet; or new sulfur iswithdrawn fromthe 'iirum "9 rr ma f'poi'nt intermediate the top and steam f'of the" -'-1'ayer of molten sulfur by means offline "21, pump 23 and line 25 ahd dhaii gd to 'a heating T5011 "21 located 'in a suitable furnace or ea er. In {the ten 21 themol'ten "si'ilfurd's -heated "to a'tefli'per'ature abov'e "450 3C. "in order that the sulfur win at flea's'tin part-be cbhvfteil t9 va or; in the am s. From the heating -"ooi l 21 he sulfurvapor or li'quid, 'as"t'hecase*may be, *dependmg upqn the pressure, passes through line 23 an valve 30 nt'isfbh t'op the drum '9 If desired, "a *part' or all of "the crude sul fur fchafr'ge may 'b'e mixed with the heateizl sulfur n'ii xtiife "entering the drum "9 "through line 29 b 'fcaium the-crude inoltemsul'fur or *afpai't 'thredrltofpass -thi-ough line 31 c'ofitrdl-led by valve 33. The temperature in the drum J is ifiaiiitairiedfabovef445C. merder to peIm'it SiilE iii"tofvaporizeairdflescape from theto'p of the dramtnrcug vvap r lmeas. v r

I 'rhetruue'mmen sulfur inletnters thefdrum 9 a heenddppositefthat from"which-sulfur is witlfd for "ei'reuiatioh "ankr scum i's remove'd fro" the surface 'o' f"them'olten sulfur, thereby perm tting the "scum to rise 'to the surface "and the sludge to "settle before the "sludge "reaches p npo nt-or tne scum" *sulfur -recyj etraw- "offs. "We"f5i"fer to intro uce crudje sulfur "into tiieiifumabovetnefievrtfthenrditn sulfurin If desired, a vertical imperforate baffle, shown in the drawing as 31, may be placed across the drum between scum draw-on" I l and the recirculating line 2!. The bafiie will extend above the level of the sulfur body, but will not extend to the bottom of the drum, thereby permitting passage of liquid from one end to the other end of the drum beneath the baffle. By using a baffle the sulfur recirculating withdrawal line 2| can extend approximately to the top of the sulfur body, as indicated in the drawing by dotted line 39, without running the risk of having scum pass into the recirculating line. By moving the top of the recirculating line 2| to the surface of the molten body, the likelihood of sludge passing into a recirculating line is substantially eliminated.

Liquid level control I!) is adapted to open and close valve 6 in line 5, thereby functioning to hold the level in the drum 9 constant. The recirculating rate through line 2|, pump 23, line 25 and heater 21 is held constant. The firing of the heater may be regulated by a conventional furnace firing control system regulated by temperature and/or pressure in the drum 9 in order to provide the required volume of sulfur vapor through the line 35 at the established temperature and pressure. Thus, when the pressure in the drum 9 increases thereby indicating an increase in the amount of sulfur vapor being produced, the heat in the heater will be cut down and vice versa. When the pressure of the sulfur vapors is reduced below a given point, the amount of heat in the heater will be increased.

As previously pomted out, sludge and scum may be dra'wn-ofi' intermittently or continuously. We prefer to withdraw the scum and sludge intermittently by manual control or by means of a cycle controller WhlCh will periodically permit sludge and scum to be withdrawn from the drum.

The temperature at which sulfur vapor leaves the drum 9 will depend on the purpose for which the sulfur vapor is to be used. Where the sulfur is to be condensed to solid sulfur, the temperature of vaporization will be only slightly above the boiling point of the sulfur. Where the sulfur is used for chemical processing, the sulfur may in some cases be heated directly in the boiler to reaction temperature by maintaining the boiled pressure at a suitable value; in other cases the sulfur vapors from the boiler may be further heated in an outside superheating section. For example, in the preparation of CS2 by reaction of sulfur vapors and hydrocarbon gases such as methane, the sulfur may be vaporized at such a pressure that the vapor escaping through line 35 may be at a temperature of GOO-700 C. or the vaporization may take place at substantially atmospheric pressure and corresponding temperature followed by subsequent superheating to de sired reaction temperature at substantially atmospheric pressure. The choice may depend on the pressure at which it is desired to operate the CS2 reaction.

The sulfur boiler serves as a receptacle to which molten sulfur is returned and in which it is boiled, has impurities removed and sulfur vaporized for use in subsequent reactions. By regulation of the pressure in the boiler, sulfur vapor at various degrees of superheat can be obtained. The specific application mentioned, that the sulfur vapor is to be prepared for reaction in carbon disulfide synthesis operations, is only one example of uses to which the sulfur vapor can be put, for any process which employs sulfur vapor as a 4 reactant at any temperature can be served by the apparatus. All that is necessary is appropriate regulation of the boiler temperature and pressure to generate the volume of sulfur vapor needed at the pressure and temperature desired.

Referring more particularly to Figure 2, there is shown a heater 21 which may be substituted for-the heater 2? of Figure 1 where thermal circulation of the sulfur is used instead of forced.

circulation. In the event a heater of the type shown in Figure 2 is used, the pump 23 will be eliminated. In this case liquid sulfur at or near its boiling point, from the drum 9 will enter through the line 25 into the header 40 at the bottom of the heater and will pass upwardly through the parallel tubes 4| to the upper header 42. Molten sulfur and sulfur vapors will leave the heater through line 29 and pass to drum 9 as shown and described in connection with Figure 1. A suitable heating element such as a gas burner 43 is provided in the bottom of heater 21' and a flue 44 is provided at the top of the heater through which combustion gases escape.

It will be seen, therefore, that we have devised a novel method and apparatus for producing sulfur vapors from crude sulfur which vapors may be condensed or may be used directly in chemical processes such as for example, preparation of carbon disulfide.

It is claimed:

1. The method of vaporizing crude sulfur comprising charging crude molten sulfur directly to a closed vaporizing zone, maintaining a body of molten sulfur in said zone, withdrawing scrum from the surface of said body of sulfur and withdrawing sludge from beneath said body of sulfur, continuously circulating sulfur substantially free of scum and sludge from said sulfur body to a tubular heater and back-to said vaporizing zone, heating the sulfur in said heater sufficiently to vaporize sulfur in said zone, withdrawing sulfur vapors from said vaporizing zone and eliminating said scum and sludge from the system without passing through said tubular heater.

2. Method in accordance with claim 1 in which the sulfur is withdrawn from an intermediate point in said body of sulfur in the vaporizing zone for circulation to said tubular heater and back to the vaporizing zone.

. CHARLES A. PORTER.

GEORGE W. ROLLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. THE METHOD OF VAPORIZING CRUDE SULFUR COMPRISING CHARGING CRUDE MOLTEN SULFUR DIRECTLY TO A CLOSED VAPORIZING ZONE, MAINTAINING A BODY OF MOLTEN SULFUR IN SAID ZONE, WITHDRAWING SCRUM FROM THE SURFACE OF SAID BODY OF SULFUR AND WITHDRAWING SLUDGE FROM BENEATH SAID BODY OF SULFUR, CONTINUOUSLY CIRCULATING SULFUR SUBSTANTIALLY FREE OF SCUM AND SLUDGE FROM SAID SULFUR BODY TO A TUBULAR HEATER AND BACK TO SAID VAPORIZING ZONE, HEATING THE SULFUR IN SAID HEATER SUFFICIENTLY TO VAPORIZE SULFUR IN SAID ZONE, WITHDRAWING SULFUR VAPORS FROM SAID VAPORIZING ZONE AND ELIMINATING SAID SCUM AND SLUDGE FROM THE SYSTEM WITHOUT PASSING THROUGH SAID TUBULAR HEATER. 